Contribution to the embryology ofMelampyrum pratense L.

Abstract

InMelampyrum pratense the anther is tetrasporangiate and anther wall consists of epidermis, fibrous endothecium, a transitory middle layer and glandular tapetum. The division of pollen mother cell is simultaneous. At shedding, the pollen grains are 2-celled, 3-colpate and spheroidal. The gynoecium is superior and the ovary is bicarpellary, syncarpous with two tenuinucellate, unitegmic ovules in each locule. A coenomegaspore with 1+3 arrangement of nuclei develops into a 7-nucleate embryo sac. The female gametophyte is tetrasporic and 7-nucleate. Theab initio cellular endosperm is haustorial. The chalazal haustorium is large, binucleate and highly aggressive. The 8–16 nucleate micropylar haustorium is unicellular with 2–4 tubular processes, one of which is longer and aggressive.